031
FXCA62 TJSJ 240820
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
420 AM AST SUN MAY 24 2026
..NEW SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST
KEY MESSAGES
ISSUED AT 411 AM AST SUN MAY 24 2026
* SIMILAR TO PREVIOUS DAYS MORNING SHOWERS WILL CONTINUE TO MOVE
ACROSS THE WINDWARD AREAS OF PUERTO RICO AND THE U.S. VIRGIN
ISLANDS. THEN, AFTERNOON CONVECTIVE ACTIVITY WILL RESULT IN
SHOWERS AND ISOLATED THUNDERSTORMS, ACROSS CENTRAL AND WESTERN
PUERTO RICO.
* BREEZY TO LOCALLY WINDY CONDITIONS WILL CONTINUE THROUGH THE
MIDWEEK. SECURE LOOSE OBJECTS, ESPECIALLY ALONG COASTAL AREAS.
* MODERATE TO FRESH EASTERLY WINDS WINDS WILL RESULT IN CHOPPY
SEAS AND A MODERATE RISK OF RIP CURRENTS ACROSS MOST LOCAL
BEACHES, LIKELY INCREASING TO A HIGH RISK BY MONDAY.
* A SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH AT LEAST
TUESDAY MORNING FOR PORTIONS OF THE OFFSHORE ATLANTIC WATERS.
SMALL CRAFT OPERATORS SHOULD CONTINUE TO EXERCISE CAUTION
ELSEWHERE.
SHORT TERM(TODAY THROUGH TUESDAY)
ISSUED AT 411 AM AST SUN MAY 24 2026
SIMILAR TO PREVIOUS DAYS, WEATHER CONDITIONS WERE VARIABLE DURING
MOST OF THE OVERNIGHT HOURS, WITH FAST-MOVING SHOWERS AFFECTING
PORTIONS OF EASTERN, SOUTHEASTERN, AND NORTHERN PUERTO RICO, WITH NO
IMPACTS ACROSS THE AREA. ACROSS THE U.S. VIRGIN ISLANDS, CULEBRA,
AND VIEQUES, MAINLY FAIR WEATHER PREVAILED UNDER MOSTLY CLEAR TO
PARTLY CLOUDY SKIES. MINIMUM TEMPERATURES RANGED FROM THE MID TO
UPPER 70S ACROSS COASTAL AND URBAN AREAS, AND FROM THE MID TO UPPER
60S ALONG THE CENTRAL MOUNTAIN RANGE. EASTERLY WINDS PREVAILED AT 5
TO 10 MPH, WITH OCCASIONAL HIGHER GUSTS AND LAND BREEZE VARIATIONS.
ANOTHER ACTIVE DAY IS ANTICIPATED ACROSS THE REGION TODAY AS DEEPER
MOISTURE CONTINUES TO FILTER INTO THE FORECAST AREA. PRECIPITABLE
WATER (PWAT) CONTENT OF 1.80 TO 2.0 INCHES, COMBINED WITH FAVORABLE
UPPER-LEVEL DYNAMICS, WILL SUPPORT THE DEVELOPMENT OF CONVECTIVE
ACTIVITY, PARTICULARLY DURING THE AFTERNOON HOURS. HEAVY RAINFALL IS
EXPECTED ONCE AGAIN TODAY ACROSS THE INTERIOR AND WESTERN PUERTO
RICO. MID-LEVEL TEMPERATURES (700–500 MB) NEAR -8 TO -9 DEGREES
CELSIUS WILL FURTHER ENHANCE THE DEVELOPMENT OF ISOLATED
THUNDERSTORMS. MEANWHILE, A STRONG HIGH PRESSURE SYSTEM DOMINATING
THE CENTRAL ATLANTIC WILL MAINTAIN WINDY CONDITIONS ACROSS THE AREA
UNDER AN EASTERLY WIND FLOW OF 15 TO 20 KNOTS.
SIMILAR WEATHER CONDITIONS ARE EXPECTED TO PERSIST INTO MONDAY
AFTERNOON; HOWEVER, PWAT VALUES WILL DROP TO AROUND 1.40 INCHES WITH
THE ARRIVAL OF A DRIER AIR PATCH, LIMITING ACTIVITY TO LOCALIZED
SHOWERS ACROSS WESTERN PUERTO RICO. DESPITE THIS BRIEF DRYING, THE
FLOODING RISK WILL REMAIN ELEVATED ACROSS THE AREA. BY TUESDAY, PWAT
VALUES ARE EXPECTED TO INCREASE ONCE AGAIN TO NEAR 2.25 INCHES, WELL
ABOVE NORMAL CLIMATOLOGICAL VALUES AS DEEPER MOISTURE FILTERS INTO
THE AREA AND AN UPPER-LEVEL TROUGH MOVE NORTHEAST OF THE ISLANDS.
CONSEQUENTLY, ACTIVE AFTERNOONS WILL REMAIN IN THE OUTLOOK THROUGH
MIDWEEK.
SEASONAL TEMPERATURES WILL PERSIST THROUGH MIDWEEK, WITH MAXIMUM
TEMPERATURES EXPECTED TO RANGE FROM THE MID TO UPPER 80S ALONG
COASTAL AND URBAN AREAS, AND FROM THE UPPER 70S TO LOW 80S IN THE
HIGHER ELEVATIONS.
LONG TERM(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 411 AM AST SUN MAY 24 2026
A WET AND SOME SLIGHTLY UNSTABLE WEATHER PATTERN IS EXPECTED TO
DEVELOP ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS ON WEDNESDAY
AS TROPICAL MOISTURE MOVES ACROSS THE REGION AS SUGGEST THE GFS AND
THE ECMWF GLOBAL MODEL GUIDANCES. PWAT VALUES FROM THE MOISTURE
ARRIVING IN THE ISLANDS ARE FORECAST TO RANGE BETWEEN 2.00 AND 2.16
INCHES, WHICH IS WITHIN THE NORMAL CLIMATOLOGICAL RANGE FOR THE
SEASON. AT THE SURFACE, A BROAD HIGH PRESSURE OVER THE CENTRAL
ATLANTIC WILL PROMOTE EAST-SOUTHEASTERLY WINDS, FAVORING WARM
CONDITIONS ACROSS NORTHERN AND WESTERN PUERTO RICO, RESULTING IN
HEAT INDICES IN THE 100S. ALOFT, SOME INSTABILITY WILL BE PRESENT
DUE TO A LOW-PRESSURE SYSTEM NEAR 250 MB REFLECTING INTO THE MID-
LEVELS AROUND 500 MB, ENHANCING UPPER-LEVEL SUPPORT FOR SHOWER AND
THUNDERSTORM DEVELOPMENT. UNDER THIS PATTERN, PERIODS OF SHOWERS AND
ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS THE LOCAL WATERS AND
WINDWARD SECTORS DURING THE MORNING HOURS, FOLLOWED BY STRONGER
CONVECTION ACROSS THE INTERIOR AND NORTHWESTERN PUERTO RICO DURING
THE AFTERNOON. URBAN AND SMALL-STREAM FLOODING, PONDING OF WATER ON
ROADS, REMAIN POSSIBLE DUE TO SLOW-MOVING SHOWERS. FREQUENT
LIGHTNING AND GUSTY WINDS WILL ALSO POSE HAZARDS NEAR THE STRONGEST
THUNDERSTORMS. ACROSS THE U.S. VIRGIN ISLANDS, SHOWER ACTIVITY WILL
BE MORE LIMITED AND FAST-MOVING, ALTHOUGH ISOLATED PONDING OF WATER
CANNOT BE RULED OUT. ADDITIONALLY, BY LATE WEDNESDAY INTO
THURSDAY, THE NASA GODDARD EARTH OBSERVING SYSTEM MODEL V5 SUGGEST
AN INCREASE OF THE PARTICLES OF SAHARAN DUST ACROSS THE ISLANDS.
FROM THURSDAY THROUGH SATURDAY, IMPROVING CONDITIONS ALOFT NEAR 250
MB WILL GRADUALLY PROMOTE A MORE STABLE WEATHER PATTERN ACROSS THE
FORECAST AREA. AT THE SURFACE, STRENGTHENING HIGH PRESSURE SPREADING
INTO THE EASTERN ATLANTIC WILL TIGHTEN THE PRESSURE GRADIENT AND
SHIFT WINDS MORE FROM THE SOUTHEAST, RESULTING IN BREEZY TO LOCALLY
WINDY CONDITIONS. THIS WIND FLOW WILL SUPPORT A WARMING TREND ACROSS
THE ISLANDS, AS FORECAST 925 MB TEMPERATURES SHOW. HEAT INDICES ARE
EXPECTED TO REACH ELEVATED LEVELS EACH AFTERNOON, ESPECIALLY ACROSS
NORTHERN, WESTERN, AND URBAN SECTIONS OF PUERTO RICO, INCREASING THE
RISK OF HEAT-RELATED ILLNESSES FOR SENSITIVE POPULATIONS. ALTHOUGH A
MORE STABLE PATTERN IS FORECAST OVERALL, LOCAL EFFECTS AND DAYTIME
HEATING WILL STILL SUPPORT AFTERNOON CONVECTION EACH DAY,
PARTICULARLY ALONG THE NORTHWESTERN QUADRANT AND PORTIONS OF THE SAN
JUAN METROPOLITAN AREA. BRIEF PERIODS OF HEAVY RAINFALL, LIGHTNING,
AND GUSTY WINDS WILL REMAIN POSSIBLE, WITH THE STRONGEST ACTIVITY
OCCURRING. BY SUNDAY, A SURFACE TROUGH DEVELOPING OVER THE WESTERN
ATLANTIC WILL PROMOTE A MORE SOUTHERLY WIND FLOW ACROSS THE REGION
WHILE PWAT VALUES DECREASE CLOSER TO AROUND 1.60 INCHES. THIS
PATTERN MAY CONTINUE THE WARM CONDITIONS ACROSS THE ISLANDS WHILE
MAINTAINING ISOLATED TO SCATTERED AFTERNOON CONVECTION, MAINLY OVER
WESTERN AND NORTHWESTERN PUERTO RICO.
AVIATION
(06Z TAFS)
ISSUED AT 411 AM AST SUN MAY 24 2026
MAINLY VFR CONDS EXPECTED ACROSS ALL TAF SITES. FAST MOVING SHRA
WILL RESULT IN -SHRA/VCSH ACROSS THE TJSJ/TIST/TISX THRU 24/14Z.
AFTN SHRA/TSRA WILL DEVELOP ACROSS CENTRAL, WESTERN PR, AND
DOWNWIND FROM EL YUNQUE POSSIBLY RESULTING IN BRIEF MVFR/IFR CONDS
OVER TJBQ/TJSJ BTWN 24/16-22Z. SCT-BKN CIGS BTW FL030-050 AND MTN
TOPS OBSCD EXPECTED ACROSS ALL THE ISLANDS. E WINDS UP TO 15-20
KTS AFTER 24/14Z, WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS,
DECREASING TO 5-10 KTS AFT 24/23Z.
MARINE
ISSUED AT 411 AM AST SUN MAY 24 2026
MODERATE TO FRESH EASTERLY WINDS WILL PERSIST ACROSS THE REGIONAL
WATERS THROUGH NEXT WEEK AS STRONG HIGH PRESSURE REMAINS ANCHORED
OVER THE CENTRAL ATLANTIC. THIS PATTERN WILL MAINTAIN CHOPPY TO
ROUGH SEAS OF UP TO 7 FEET ACROSS THE OFFSHORE ATLANTIC WATERS AND
LOCAL PASSAGES. AS A RESULT, A SMALL CRAFT ADVISORY REMAINS IN
EFFECT THROUGH AT LEAST TUESDAY MORNING FOR PORTIONS OF THE OFFSHORE
ATLANTIC WATERS, WHILE SMALL CRAFT OPERATORS ELSEWHERE SHOULD
CONTINUE TO EXERCISE CAUTION. IN ADDITION, ISOLATED AFTERNOON
THUNDERSTORMS MAY DEVELOP NEAR THE WESTERN COASTAL WATERS OF PUERTO
RICO EACH DAY, PRODUCING LOCALLY HIGHER WINDS AND SEAS.
BEACH FORECAST
ISSUED AT 411 AM AST SUN MAY 24 2026
THE PERSISTENT EASTERLY WIND FLOW WILL MAINTAIN A MODERATE RISK OF
RIP CURRENTS THROUGH THE WEEKEND FOR MANY NORTH- AND EAST-FACING
BEACHES OF PUERTO RICO, CULEBRA, VIEQUES, AND PORTIONS OF THE U.S.
VIRGIN ISLANDS. WINDS ARE EXPECTED TO STRENGTHEN FURTHER EARLY NEXT
WEEK AS THE ATLANTIC PRESSURE GRADIENT TIGHTENS.
CONSEQUENTLY, THE RISK OF RIP CURRENTS WILL LIKELY INCREASE TO HIGH
ACROSS MANY EXPOSED BEACHES MONDAY INTO TUESDAY. BEACHGOERS SHOULD
EXERCISE CAUTION AND HEED THE ADVICE OF LOCAL OFFICIALS AND BEACH
SAFETY PERSONNEL. AFTERNOON THUNDERSTORMS ARE ALSO POSSIBLE EACH DAY
ACROSS WESTERN PUERTO RICO; IF THUNDER IS HEARD, SEEK SHELTER
IMMEDIATELY. FOR ADDITIONAL INFORMATION AND LOCATION-SPECIFIC RIP
CURRENT FORECASTS, VISIT WEATHER.GOV/BEACH/SJU.
SJU WATCHES/WARNINGS/ADVISORIES
PR...NONE.
VI...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 6 AM AST TUESDAY FOR AMZ711.
SHORT TERM...GRS
LONG TERM...LIS
MARINE/BEACH FORECAST...ICP
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